THE FRAGRANT CALLA 21 



developed in the past are still in operation every- 

 Mhere about us. Many people are disposed to 

 think of natural selection as a principle referring 

 to past times and to the development of organ- 

 isms long since perfected. 



In point of fact past times are like present 

 times in the operation of their laws. The re- 

 actions between organism and environment are 

 now what they always were. Xo race is perfected, 

 no organism freed from the struggle for exis- 

 tence; although, of course, under the conditions 

 of civiHzation the operation of 'natural selection" 

 may be modified through man's influence, and the 

 conditions of life for a given organism radically 

 changed by artificial selection. 



Evolution Through ^Iutatiox 



But let us not forget our theme. With the 

 case of the fragrant calla to furnish our text, I 

 was about to speak of those variations from the 

 normal on the part of any given organism which 

 lie outside the ordinary- range of variation and 

 which therefore constitute so definite and pro- 

 nounced a departure that they have long been 

 spoken of as 'sports.'* 



To these some of the present-day evolutionists, 

 following Professor Hugo de Vries, give the 

 name of "mutations." 



